Practice question
Question
A ball is thrown upwards at 40m/s from a 25m tower. What is the time taken to hit the ground? (Take g\=10m/s2)
Explanation
y=v0t−12gt2, y=−25, v0=40m/s. As per NCERT Chapter 3, equations v=u+at, s=ut+½at², v²=u²+2as describe uniformly accelerated motion. Applying correct signs and units gives 9 s as the result, so option B is correct.